Piezoelectric actuators transform electrical energy into mechanical energy, and because of their compactness, quick response time and accurate displacement, they are sought after in many applications. Polycrystalline piezoelectric ceramics are technologically more appealing than single crystals due to their simpler and less expensive processing, but have yet to display electrostrain values that exceed 1%. Here we report a material design strategy wherein the efficient switching of ferroelectric–ferroelastic domains by an electric field is exploited to achieve a high electrostrain value of 1.3% in a pseudo-ternary ferroelectric alloy system, BiFeO₃–PbTiO₃–LaFeO₃. Detailed structural investigations reveal that this electrostrain is associated with a combination of several factors: a large spontaneous lattice strain of the piezoelectric phase, domain miniaturization, a low-symmetry ferroelectric phase and a very large reverse switching of the non-180° domains. This insight for the design of a new class of polycrystalline piezoceramics with high electrostrains may be useful to develop alternatives to costly single-crystal actuators.

压电致动器将电能转换为机械能，并且由于其紧凑，响应时间短和位移准确等特点，在许多应用中都受到追捧。多晶压电陶瓷由于其工艺简单，成本较低而在技术上比单晶更具吸引力，但电应变值仍超过1％。此处我们报告一个材料设计策略，其中通过电场的铁电-铁弹域的有效切换被利用，以实现在一个伪三元铁电合金系统的1.3％的高电致伸缩值，的BiFeO ₃ -PbTiO ₃ -LaFeO ₃。详细的结构研究表明，这种电应变与多种因素相关：压电相的大自发晶格应变，磁畴小型化，低对称铁电相和非180°磁畴的非常大的反向开关。对于新型具有高电应变的多晶压电陶瓷的设计的这种见识，对于开发昂贵的单晶致动器的替代品可能是有用的。